Ferrosilicon alloys of a definite composition.



H, C. HARRISUN.

VQHROSILICO ALLOYS 0F A DEFNITE COMPOSIUON.

APPLICATION man DEC. 14. RumA/En SEPT. xmm.

9 l 3%, l 29a Patented Apr. 6, 1915.

SoLuam'TY Cum/ES FOR FERRO SaLlcoNS FROM OTOFOS|UCON parrain sracrns rarnnar cierren.

HERBERT CHAMPION HARRISON, OF LOCKPORT, NEW' YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO ELECTRO METALLURGICAL COMPANY, A COPORATION F WEST VIRGINIA.

FERROSILICON ALLOYS OF A DEFINITE COMPOSITION.

Specification of Letters Patent.

-- Patented Apr. 6, 1915.

Application filed December 14, 1909, Serial No. 533,110. Renewed September` 17, 1914. Serial No. 862,256.

' To all 'whom tw/ay concern:

Be it known that I, HERBERT CHAMPION HAnnisoN, a subject ofthe King ofGrreat Britain, residing at Lockport, Niagara county, and State of New' York, have invented certain new iand useful Improvements in Ferrosilicon Alloys of. a Denlte Composition; and I do hereby declare the following to `be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to ferrosiliconalloys and has for its object to produce prod. ucts of such a nature as will enable the user to attain more uniform results than heretofore.

Vith these ends in view the invention consists in the series of definite alloys more fully hereinafter disclosedA and particularly pointed' out in the claims. l

Referring to the accompanying `drawings forming apart of this specification: Figure l is a diagram showing solubility curves for 'A ferrosilicon alloys from zero to 54 per cent. silicon content. Fig. 2 Ais a diagram illustrating the Irelative freezing and melting points of the various alloys of from 33 per cent. silicon to 54 per cent. silicon.

It is well known that the chemical cornpound FeSi exists, and I have shown in Amy pending application #510,477 filed July 30, 1909, forferrosilicon products and methods of producing the same that the compound FeaSi7 exists; and therefore in an alloy consisting of iron and silicon between the limits of pure ironand no silicon, and pure silicon and no iron we have these two compounds. I have now demonstrated that in the series Fe; FeSi; FeaSiT; and Si that any two of these members when taken consecutively will when liquid dissolve into each other in all proportions, but when just solid,

each is mutually insoluble in the other.-

bols Fe and Si are used to indicate metallic ir'on and metallic silicon respectively.

It follows from the foregoing that all the alloys between Fe' and' FeSi consist of solid vmixtures of Fe and FeSi in varying promula FesSi, which itself consists of a solidcrystal of pure FeSi, and a crystal of pure iron. This enables, one to foretell with a great deal of certainty, the eXact constitution of all alloys between the above limits. That is to say, on cooling an alloy from the liquid state which lies between the limits of this eutectic and `pure iron, the pure iron in eX- -cess will crystallize out .first until the remainder reaches the composition of the eutectic, when without a further drop in temperature which `now remains constant the eutectic will crystallize out until the whole mass is solid. The line AE1 in Fig. 2 represents the freezing points and compositions of the various alloysthat may exist between ure iron and the eutectic Fe3Si1; the point 1 corresponding to the compositions of this eutectic and also to its freezing point. .And again, on cooling an alloy which lies between the limits of the eutectic and FeSil, first, that FeSi which is an excess will crystallize out until the composition of the remainder reaches the composition of the eutectic. Thereupon this eutectic will crystallize out at a constant temperature until the whole mass is solid. The line ElB also represents the'freezing points and compositions of the various alloys that may eXistbetween the eutectic F eaSi arid F eSi while the point B corresponds to the composition and freezing point of the compound FeSi.

I have discovered that in this series of alloys neither Fe'ZSi7 nor free silicon can exist as such.' I have been enabled to prove this by dissolving all the iron in these-alloys in hydrochloric acid and determining the silicon in the residue, which silicon in said residue was-found to exist in the form of silicia. I-Iad it existed as silicon in the original alloy it would have been unattacked and would have been weighed as silicon instead of silica. In the same way had FeaSi7 been present-in 4these alloys all of the iron would not have been soluble in the hydro chloric acid sinceA this compound I have demonstrated to be insoluble in that reagent.

By the same .procedure I have demonstrated that all the alloys between F eSi, and FeSSi7 consists ofsolid mixtures of pure FeSi and pure FesS7 in varying proportions. And I have Vfound that a second eutectic corre* 'spending to FeiSi8 `which is itself a crystal of FeSi together with a crystal-of Fes-Si7 exists.v Upon cooling an alloy from the ,liquid existing between the limits FeSi and Fe4Si8,.thefFeSi in excess crystallizes out first until the composition of the remainder `reachesthat of the second eutectic when at a constant temperature the latter will crystal- ]ize out until the mass is solid. The line BE2.

in like manner represents the freezing points and the compositions of these various latter alloys. *Also upon cooling an alloy between the limits of the secondeutectic and FesSiT,

that FesSi; which `is in excess will crystal-v lize out rst, and until the composition of the remainder reaches that of the second eutectic, .when at a const ant temperature this latter will crystallize out until the whole' mass is solid. rIhe line E2C represents the compositions and freezing points of these said alloys.

In this series of alloys neither free iron nor .free siliconexists;- and I have proved this `by showing that when any such alloys are treated with hydrochloric acid the iron which is .dissolved outtogether with the `residue which is left, adds up to considerably more than 100 per cent. and that in every case the excess of weight of the residue', which consists .of silica and Fe3Si7, is due tothe fact that the silicon which was combined with the iron dissolved is weighed in the said residue as silica and not silicon. On the other hand theactual amount 'of silicon in the silicia is found in every canse to be that amount which wouldhave combined with thedissolved iron as FeSi; thus Si and that a eutectic exists corresponding to FeaSi9 which is itself'composed of a crys` Upon tal of FesSi7 and a crystal of silicon. cooling such an alloy from the Aliquid state between the limits of FeSi7 and FeSiJ that Fei7 which is in excess will first crystallize out until .the remainder reaches the composition corresponding toV theA third Ieutectic,

whereupon this latter will crystallilze out at a constant temperature until the whole mass is solid.' The line @E3 represents the com- .positions and freezing points of these last mentioned alloys. Upon cooling ian alloy between the'limits of the third eutectic corresponding tolleaSi9 and- Si, that silicon also discovered that neither` free iron nor' free FeSiexists as the whole-of the product is insoluble in vhydrochloric acid. The foregoing results may be graphically illustrated as in Fig. 1, wherein the line 1 represents a solubility curve which passes through a series 4of seven illustrative `determinations that were actually carried out. In this `igure the percentages of silicon are plotted vertically land the percentages of solubilities in hydrochloric acid of the' alloysillustrated are plotted horizontally. The `solubility of FeSi, is 66.2 per cent. because all its iron is soluble whereas the solubility'v of FeaSai7 is zero, because none of its iron is soluble; and these two compounds markthe extremities of line 1. The other alloys illustrated inA eri;V

Fig. l have solubilities vcorresponding to their positions on said line. These determinations of solubilities .in hydrochloric acid show that the solubilities found to actually existinpractice in the case of alloys Varying between 37.24 per cent. and 54 percent. silicon content agree closely with what would be necessary if all alloys between 33 per cent. and 54 per cent. of silicon consisted of solid mixtures of Fe3Si7 and FeSi. And in no case do these determinations agree with an assumption that the alloys consist of any other constitution, for if they did these would fall on one or the other of the hypothetical curves 2, 3 and 4. The line 2 represents the solubilities of mixtures of 3 represents mixtures of FeaSi7 with either the hypothetical FesSi2 or the hypothetical FegSi; and the line 4 represents mixtures of FeaSi7 with Fe. Since no determinations lie on or near any of the lines other than, line 1, and all of them lie on line 1, the igure represents graphicallythe fore oin results.

The foregoing information ays are the constitutions and compositions of the whole range of alloys, and enables one to produce at will by following the procedure below not only any particular alloy of an unvarying character, but a whole series of alloys which will always behave the same when steel is treated therewith.

In order to produce an alloy which willbe ideata@ uniform in its behai'ior and unvarying in.

cal reduction of the silica together with.

suoli an excess of carbon as may be found desirable from practical considerations; l apportion the input of power to the furnace to the size of the furnace operated and in such manner as to insure a practically theoretical yield of the alloy sought from the charge material, all as fully set forth in connection with the manufacture of .Fegii7 in my copending application #530,787 filed ADecember l, 1909.

when employing dierent temperatures,'

which is not the case at present. He knows the temperature to which the steel must he raised to melt the alloy and therefore he knows that a' higher temperature must be employed to chemically break up the alloy in the metal. He knows whether it Will be endothermic or'exothernlic in the melt, and therefore whether it will chill or heat the metal. in fact, after the steel maker has once attained perfection with a definite alloy, he can be assured of indefinitely repeating his success which is not the case at present.

Oi course it is evident to those skilled in the art that the foregoing principles are applicable 'to alloys in general, and therefore I do not wish to be limited to any specific` alloys except as may be required by the claims. i

TWhat l claim is l. The herein described ferro alloy having a definite composition and a definite constitution, comprising solid mixtures of definite chemical compounds containingiron, substantially as described.

, 2. rl`he herein described ferro alloy having a definite composition and a definite constitution, comprising solid'mixtures of definite chemical compounds containing iron and silicon, substantially as described.

3. rlhe herein described ferro alloy having a deinite'composition and a definite constitution consisting of a plurality of definite chemical compounds of iron and silicon, substantially as described.

ln testimony whereof, li aix my signature, in presence of two Witnesses.

HERBERT C. HARRISON.

Witnesses:

T. A., WITHERsrooN, d. FRED KELLEY. 

